Placentography by sonar.
D002585:Cesarean Section; D005260:Female; D006801:Humans; D008722:Methods; D010920:Placenta; D010923:Placenta Previa / Q000175:diagnosis* / Q000000981:diagnostic imaging; D011247:Pregnancy; D011859:Radiography; D014465:Ultrasonics / Q000295:instrumentation; D014463:Ultrasonography